[4] [4] ZHENG W B, YIN H T, WANG A Q, et al. Development of an automatic reading method and software for pointer instruments ［C］//Proceedings of 2017 First International Conference on Electronics Instrumentation & Information Systems. Harbin, China: IEEE, 2017: 1-6.

[7] [7] YANG Z J, NIU W N, PENG X J, et al. An image-based intelligent system for pointer instrument reading ［C］//Proceedings of 2014 4th IEEE International Conference on Information Science and Technology. Shenzhen, China: IEEE, 2014: 780-783.

[11] [11] WANG C, FANG Y S, JIA L. The comparison of Canny and structured forests edge detection application in precision identification of pointer instrument ［C］//Proceedings of 2018 Chinese Control And Decision Conference. Shenyang, China: IEEE, 2018: 6361-6365.

[12] [12] MA Y F, QI J, WAND J J, et al. An automatic reading method of pointer instruments ［C］//Proceedings of 2017 Chinese Automation Congress. Jinan, China: IEEE, 2017: 1448-1453.

[13] [13] HAN J L, LI E, TAO B J, et al. Reading recognition method of analog measuring instruments based on improved Hough transform ［C］//Proceedings of the IEEE 2011 10th International Conference on Electronic Measurement & Instruments. Chengdu, China: IEEE, 2011: 337-340.